Line transformer between Directstream and M700, instead of preamp?


I have had DS Jr and a pair of M700 for a year, and am happy with it.

I heard that noise floor and sound quality can be improved by adding a Line transformer, such as Jensen Iso-Max, RCA MI-11713, between Jr and M700. How does the sound quality compare with that of preamp? What about with DS Sr?

Due to budget constraints, one way to upgrade my system is to upgrade DS Jr with DS Sr. The other way is to keep DS Jr and add line transformer in place of preamp. Which will be recommend?

DS Sr. would be better.

I have a DSD Sr. which I originally ran single-ended out. I then put a Decware Z-Bit between the DSD Sr. and my power amps, which allowed me to use the balanced outputs on the DAC. The Z-Bit converts the balanced signal to single ended. That was a marked improvement as I feel the output voltage on the unbalanced outputs is too low for my liking.

I then learned about using repeat coils to tranform balanced to unbalanced. The best of the best is the Western Electric REP111C. I picked up one that was built/finished in a nice enclosure with high quality wiring and connectors. It bested my Z-Bit and that is how I currently run my DSD Sr.

I am certain it will improve the sound quality of the Jr. by utilizing its balanced outputs. Overall, dynamics are much improved - making the music more exciting to listen to. This is especially true with tracks that tend to be rather lean using the DSD’s single-ended ouputs. These vintage repeat coils are relatively inexpensive so in my opinion, worth exploring as an alternative option to jumping to the DSD Sr. You can always move up to the Sr. later and the great thing is, the repeat coil works brilliantly on the Sr. I like my Sr. with the repeat coil more then without. So, no money lost if you happen to invest in one.

Again, if you go this route, I highly recommend the Western Electric REP111C. Do some investigating and I feel you will come to the same conclusion.

1 Like

E - did you have a Jr. before you got a Sr.?

Sophia - you have a Better-than-Most-People-on-the-Planet DAC and great amps. Get a great preamp. At least audition one. Just sayin’.

If you wire in a box between, it better be something that offers enhanced SQ along with added control (such as a variable gain stage). I would argue (and have hereabouts) that a good pre in between your DAC and Amps is the way to go.

Let’s say you buy a preamp and ICs that cost the difference between the cost of the Jr. and Sr. You now have a much better-sounding, more flexible system, rather than just an (arguably) better DAC.

If you buy a $250 box with wires that go with that, you are degrading what you have, whatever that box does.


Jeff where did you find it in such a nice enclosure ?

I was a seller on Ebay. Very nice build quality and it arrived as described. Hard to find them in this configuration I have found.

Adding a preamp is a good solution, such as Spectral 30 or Meister 7 (200V FET) preamps. I’m interested in a preamp that uses Fetrons (hybrid JFET circuit device), which exhibit virtually no aging, and also other higher gain than do their vacuum tube counterparts. Unfortunately, they tend to be pricey, and I will need to save money for a while. That’s why I’m considering using line transformers in the interim while I save up. Or can anyone recommend other good preamps that are more budget priced?

Where can get Western Electric REP111C? Compared to Jensen Iso-Max, How much better is it? It appears that Jensen is easier accessible on the market.

Where can get Western Electric REP111C? If I can’t find WE REP111C like the one you have, do you think Jensen will be comparable? If you are willing to sell WE, please let me know.

My new monoblocks are balanced so I will be removing it from my DS Sr. so I can go straight to a balanced pre-amp or the monoblocks (no preamp). The question is, do I want to put it in between my Oppo UDP-205’s balanced outputs and my single ended pre-amp? I haven’t decided but if I do put it up for sale, you have first right to refusal.

I was fortunate enough to find mine on eBay already built in the enclosure above. I personally have not auditioned the Jensens, but there are plenty of user who have and preferred the sound of the WE REP111C. However, it is Western Electronics technology that Jensen now uses in their transformers. Western Electric sold them the technology years back. I think the vintage repeat coils sound so good due to the metallurgy of the period in which these were manufactured.

Are you using the device to color/enhance the sound or just to isolate ground like Jensen transformers?

The primary purpose is to take advantage of the higher voltage balanced outputs on the DS Sr. Prior to my monoblocks, my amplifier was single-ended so this repeat coil converted the higher voltage balanced signal to single-ended allowing me to connect to my power amp with RCAs. Utilizing the extra voltage from the XLR outs in this manner produces a better sound, based on my experience.